KR100488857B1 - Composition of thermoplastic resin having a high resistance - Google Patents

Abstract

The present invention relates to a thermoplastic resin composition having excellent high temperature dimensional stability and improved impact resistance, and more particularly, a graft copolymer (I) of a vinyl cyanide compound-aromatic vinyl compound in which rubber latex is dispersed; Copolymer (II) having a nonlinear structure having a weight average molecular weight of 200,000 to 1,000,000 consisting of a vinyl cyanide compound and an aromatic vinyl compound; And a copolymer (III) having a linear structure having a weight average molecular weight of 100,000 to 200,000 consisting of a vinyl cyanide compound and an aromatic vinyl compound, in a specific ratio. The obtained resin composition has a high linear expansion of a conventional ABS resin. Not only solve the problems of impact strength and shrinkage shrinkage according to the coefficient, but also increase the dimensional stability at high temperature can be used very well for automotive plastic materials.

Description

Composition of thermoplastic resin having a high resistance

The present invention relates to a thermoplastic resin composition having excellent high temperature dimensional stability and improved impact resistance, and more particularly, graft copolymer (I) of a vinyl cyanide compound and an aromatic vinyl compound in which rubber latex is dispersed; Copolymer (II) having a nonlinear structure having a weight average molecular weight of 200,000 to 1,000,000 consisting of a vinyl cyanide compound and an aromatic vinyl compound; And a copolymer (III) having a linear structure having a weight average molecular weight of 100,000 to 200,000 consisting of a vinyl cyanide compound and an aromatic vinyl compound, in a specific ratio.

ABS (Acrylonitrile-Butadiene-Styrene) resin is a polymer blend having a two-phase heterogeneous structure in which rubber-like polymers such as BR, SBR, and NBR are finely dispersed in a continuous phase of an AS resin which is a glassy polymer. ABS resins are produced by changing the manufacturing method, composition and molecular weight of the resin used, type of rubber, composition, particle diameter, crosslinking degree, graft ratio, ratio of resin and rubber, or by adding a fourth new component. Can change drastically. In other words, ABS resin can produce a wide range of materials freely having properties suitable for each depending on the application.

The basic method of preparing the ABS resin is already known. For example, a styrene monomer, which is a typical aromatic vinyl compound, and an acrylonitrile monomer, which is an unsaturated nitrile compound, are grafted by using an emulsion polymerization method. It is common to be.

The ABS resin has the properties of each of the hybrid polymers at the same time, and the physical properties of the rubbery polymer, graft polymer, and matrix polymer to be used are different depending on the combination of each component to obtain the desired resin. In addition, it is not only excellent in impact resistance, chemical resistance, chemical resistance, heat resistance and mechanical strength, but also easy to be molded and used, and is widely used in electric and electronic parts, automobile parts and general goods.

ABS resin in the automotive field is not only used for interior and exterior applications such as instrument panels, console boxes, rearview mirrors, and radiator grilles, but is also painted and plated without special treatment such as special primer treatment on the molded products. Secondary processing is possible and is widely used. However, the plastic material for automobiles including the conventional ABS has a problem that the low coefficient of linear expansion and impact resistance at both high temperatures are incompatible.

In order to solve this problem, Japanese Patent Laid-Open No. 7-18189 discloses that another thermoplastic resin having a smaller modulus of elasticity than the thermoplastic resin is not dispersed in a domain matrix. In the case of forming a distributed form on the network, it has been proposed that a low coefficient of linear expansion, which is not expected with conventional products, can be obtained.

In addition, Japanese Patent Application Laid-open No. Hei 10-265644 introduces a technique of lowering the coefficient of linear expansion of a resin molded article using ultrafine calcium carbonate as a filler. However, the above techniques are merely a technique of adding and mixing fillers, and are effective in reducing the linear expansion coefficient of the resin molded article in part, but do not use the existing mold equipment due to the rapid drop in impact strength and low shrinkage rate. It does not completely solve the problem.

Accordingly, the present inventors have repeatedly studied to solve the above problems, graft copolymer made of a vinyl cyanide compound-aromatic vinyl compound dispersed rubber latex; And a vinyl cyanide compound-aromatic vinyl compound, and two kinds of copolymers having different molecular weights and structures; were mixed at a specific ratio to prepare a thermoplastic resin composition, such as impact strength and linear expansion coefficient of the resin composition. As a result of measuring the mechanical properties, it was confirmed that the coefficient of linear expansion was low, the dimensional stability was high and the impact resistance was improved, and the flow index and paintability were measured, and the moldability was excellent and the coating performance was excellent without the primer treatment. It was confirmed to complete the present invention.

Accordingly, it is an object of the present invention to provide a thermoplastic resin composition having excellent high temperature dimensional stability and impact resistance.

Still another object of the present invention is to provide a thermoplastic resin composition which is excellent in moldability and exhibits high paintability without treating a primer.

It is another object of the present invention to provide a method for producing the thermoplastic resin composition.

Still another object of the present invention is to provide a use in which the thermoplastic resin composition can be usefully used for automobile plastic materials.

The present invention provides a graft copolymer (I) of a vinyl cyanide compound and an aromatic vinyl compound in which rubber latex is dispersed; Copolymer (II) having a non-linear structure composed of vinyl cyanide compound-aromatic vinyl compound; And a copolymer (III) having a linear structure made of a vinyl cyanide compound-aromatic vinyl compound is mixed in a specific ratio.

Specifically, in the thermoplastic resin composition of the present invention, the graft copolymer (I) is contained in the total thermoplastic resin composition as the first component in 10 to 30% by weight, wherein the graft copolymer (I) is 30 to 70% by weight of the rubber latex % And a monomer mixture of 70 to 30% by weight, wherein the monomer mixture consists of 20 to 40% by weight of vinyl cyanide monomer and 60 to 80% by weight of aromatic vinyl compound monomer.

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Secondly, the copolymer (II) of the nonlinear structure having a weight average molecular weight of 200,000 to 1,000,000 is included in the total thermoplastic resin composition in an amount of 20 to 50% by weight. It consists of 60-80 weight% of monomers.

Third, the copolymer (III) having a linear structure having a weight average molecular weight of 100,000 to 200,000 is included in the total thermoplastic resin composition in an amount of 20 to 60% by weight, which is composed of 20 to 40% by weight of a vinyl cyanide monomer and an aromatic vinyl compound. It consists of 60-80 weight% of monomers.

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Hereinafter, the configuration of the present invention in detail.

The thermoplastic resin composition of the present invention is not only excellent in high temperature dimensional stability and impact resistance, but also excellent in moldability and exhibits high paintability without treating a primer, so that the thermoplastic resin composition can be suitably used for automotive interior and exterior materials.

As used herein, "rubber latex" is a component having excellent elasticity, and as a factor affecting impact resistance and the like of the thermoplastic resin composition of the present invention, natural rubber; Styrene-butadiene rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, butyl rubber, acrylonitrile-butadiene Synthetic rubbers such as rubber (acrylonitrile-butadiene rubber), chloroprene and neoprene rubber.

In addition, the "vinyl compound" mentioned in this specification means an aryl benzyl group.

In addition, the "vinyl cyanide compound" referred to in the present specification is a compound in which a part of the aryl benzyl group is substituted with a cyan group, and does not limit the type thereof in the present invention and may include a conventionally possible structure, for example, acrylonitrile ( acrylonitrile) and methacrylonitrile.

In addition, the "aromatic vinyl compound" referred to herein is a compound containing a double bond and an aromatic, that is, a benzyl group in the molecular structure, and does not limit the kind in the present invention, for example, styrene (styrene), alphamethyl styrene ( methacrylic acid derivatives such as α-methyl stylene, methyl methacrylate, butyl acrylate, N-phenyl maleimide, N-cyclo Hexyl maleide (N-cyclohexyl maleide) and anhydric maleic acid.

1) Graft Copolymer (Ⅰ)

Graft copolymer (I) which is the first component of the present invention comprises 30 to 70% by weight of rubber latex; 70 to 30 wt% of a copolymer in which a 20 to 40 wt% vinyl cyanide compound monomer and a 60 to 80 wt% aromatic vinyl compound monomer are copolymerized.

The rubber latex affects the impact strength of the final resin composition. In general, as the content thereof increases, the impact strength increases, and the impact strength changes according to the particle diameter. In particular, when the particles of the rubber latex is too small, it shows a low impact strength at the same content, if too large there is a risk of generating a crack during external impact. In consideration of this matter, in the present invention, the particle size of the rubber latex is in the range of 0.25 to 0.40 μm, and the content thereof is 30 to 70 wt%, preferably 45 to 70 wt%, based on the total content of the graft copolymer (I). Limited to%.

The other components, the vinyl cyanide compound and the aromatic vinyl compound, were determined in consideration of their mechanical strength, heat resistance, oil resistance, weather resistance, etc. while maintaining appropriate heat resistance, permeability, processability, and electrical properties.

The graft copolymer (I), which is the first component, is prepared using a conventional graft emulsion polymerization of mixed monomers of rubber latex, vinyl cyanide compound and aromatic vinyl compound. As a result, the graft copolymer obtained has a structure in which rubber latex is dispersed in a copolymer matrix of vinyl cyanide compound-aromatic vinyl compound, and the rubber latex absorbs external impact to increase the impact resistance of the material. Therefore, in the present invention, the physical properties can be controlled by including 10 to 30% by weight of the graft copolymer (I) based on the total thermoplastic resin composition. For example, if the content is less than the above range, the impact strength of the final resin is sharply lowered. If the content exceeds the above range, the impact resistance is increased, but the effect of improving the linear expansion coefficient is insignificant and the heat resistance is decreased. Kerr application usage is limited and undesirable.

2) Copolymer of Nonlinear Structure (II)

Copolymer (II) which is the second component of the present invention is polymerized by mixing 20 to 40 wt% of a vinyl cyanide compound monomer and 60 to 80 wt% of an aromatic vinyl compound monomer.

The copolymer (II) is polymerized by the conventional polymerization method at the above-described composition ratio so that the weight average molecular weight is 200,000 to 1,000,000. The copolymer (II) obtained at this time has a nonlinear structure, and can have an effect of improving the coefficient of linear expansion as it has a relatively high molecular weight. Therefore, the content of the copolymer (II) in the present invention is limited to 20 to 50% by weight based on the total thermoplastic resin composition, when the content is less than the above range, the formability and processability is improved, but the coefficient of linear expansion It is not preferable that the improvement effect of the above range is exceeded, and the linear expansion coefficient is improved, but it is not preferable because it has problems such as productivity decrease and unmelting in the extrusion process.

3) Copolymer of linear structure (III)

Copolymer (III), which is the third component of the present invention, is mixed and polymerized with 20 to 40% by weight of the same vinyl cyanide monomer and 60 to 80% by weight of the aromatic vinyl compound monomer as the copolymer (II). Do.

However, the molecular weight of the finally obtained copolymer (III) has a linear structure compared with copolymer (II), and is manufactured so that it may have a low molecular weight of 100,000-200,000. By adopting the copolymer (III), the thermoplastic resin composition of the present invention can obtain the effect of improving the heat resistance and the coefficient of linear expansion, and its content is limited to 20 to 60% by weight based on the total thermoplastic resin composition. At this time, if the content is less than the above range, the moldability and impact resistance is improved, but the heat resistance is lowered and the effect of improving the linear expansion coefficient is not obtained, which is not preferable.

The copolymer (II) and the copolymer (III) may be prepared by a polymerization method known in the art, and are not particularly limited in the present invention. For example, emulsion polymerization, suspension polymerization, solution polymerization, etc. may be applied, and molecular weight control may also be controlled by various factors such as mole ratio and reaction conditions of each monomer. have.

In addition, various additives such as pigments, dyes, antioxidants, UV stabilizers, antistatic agents, reinforcing agents, fillers, etc. may be mixed and used within a range that does not impair the physical properties, etc., depending on the use of the composition. It can be added and used suitably by the person who has.

According to a preferred embodiment, the thermoplastic resin composition according to the present invention exhibited excellent impact strength and high thermal deformation temperature despite having a relatively low linear expansion coefficient, and also showed excellent paintability.

Therefore, the thermoplastic resin composition of the present invention not only solves the disadvantages of the ABS resin, which has exhibited poor high temperature dimensional stability according to the high coefficient of linear expansion, but also can be easily used as an alternative material of the ABS resin as it exhibits excellent impact resistance and paintability. Can be.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

The thermoplastic resin composition was prepared using the composition presented by the present invention. As the graft copolymer resin (I), a resin containing rubber latex having an average particle diameter of 0.30 µm and having a graft ratio of 65% by weight was used. Copolymer (II) resin used was acrylonitrile-styrene non-linear copolymer resin having an acrylonitrile content of 28% by weight and a weight average molecular weight of 350,000, and acrylonitrile content of 28% by weight for copolymer (III) resin. Acrylonitrile-alphamethylstyrene copolymer resin having a weight average molecular weight of 120,000% and acrylonitrile-styrene copolymer resin having an acrylonitrile content of 24% by weight and a weight average molecular weight of 150,000 were used, respectively. In addition, fillers, antioxidants, lubricants and ultraviolet stabilizers were further added to improve processability and physical properties. This composition is as shown in Table 1 below.

<Example 1>

20% by weight of graft copolymer resin (I); 35% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And 45% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III) having a weight average molecular weight of 120,000. An antioxidant, ultraviolet stabilizer, and lubricant were added to the mixture, followed by melting and kneading extrusion to prepare pellets.

At this time, the extrusion was used L / D = 32, 45 mm diameter twin screw extruder and the cylinder temperature was set to 230 ℃. The prepared pellets were injection molded to prepare specimens of 100 mm × 100 mm × 3 mm.

<Example 2>

25% by weight of graft copolymer resin (I); 25% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And a specimen was prepared by molding in the same manner as in Example 1, except that 50% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III) having a weight average molecular weight of 120,000 was mixed.

<Example 3>

30% by weight of graft copolymer resin (I); 20% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And a specimen was prepared by molding in the same manner as in Example 1, except that 50% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III) having a weight average molecular weight of 120,000 was mixed.

Comparative Example 1

35% by weight of graft copolymer resin (I); 25% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And a specimen was prepared by molding in the same manner as in Example 1 except that the weight average molecular weight of 120,000 was mixed in 40% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III).

Comparative Example 2

25% by weight of graft copolymer resin (I); 15% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And a specimen was prepared by molding in the same manner as in Example 1, except that the weight average molecular weight was mixed with 60% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III) having a weight of 120,000.

Comparative Example 3

15% by weight of graft copolymer resin (I); 20% by weight of acrylonitrile-styrene nonlinear copolymer resin (II) having a weight average molecular weight of 350,000; And a specimen was prepared by molding in the same manner as in Example 1, except that the weight average molecular weight was mixed with 65% by weight of acrylonitrile-alphamethylstyrene copolymer resin (III) having a weight of 120,000.

<Comparative Example 4>

25% by weight of graft copolymer resin (I); 50% by weight of acrylonitrile-alphamethylstyrene copolymer resin having a weight average molecular weight of 120,000; And 25% by weight of acrylonitrile-styrene copolymer resin having a weight average molecular weight of 150,000, and then 10% by weight of silica was added to the total composition of the mixture, and the subsequent procedure was the same as in Example 1. Molded to prepare a specimen.

Comparative Example 5

25% by weight of graft copolymer resin (I); 50% by weight of acrylonitrile-alphamethylstyrene copolymer resin having a weight average molecular weight of 120,000; And a specimen was prepared by molding in the same manner as in Example 1, except that the weight average molecular weight was mixed with 25% by weight of acrylonitrile-styrene copolymer resin having a weight of 150,000.

<Property Evaluation>

In order to determine the physical properties of the thermoplastic resin compositions prepared in Examples and Comparative Examples, it was measured based on the evaluation method described below using a specimen prepared in advance, these results are shown in Table 2 below.

Assessment Methods

1.Impact Strength: ASTM D256

(1/4 ", 23 ℃, unit = Kgfcm / cm)

2. Melt Index: ASTM D1238

(10 Kg, 220 ℃, unit = g / 10min)

3. Heat Deflection Temperature (Softening Point): ASTM D1525

(5 Kg, 50 ° C / hr, unit = ° C)

4. Linear expansion coefficient: The coefficient of linear expansion was measured at a temperature rising rate of 10 ° C./min from 30 ° C. to 80 ° C. using a thermomechanical analyzer (TMA). (Unit = µm / m 占 폚)

5. Paintability: Urethane coating was applied to 100mm × 100mm × 3mm specimens, and the appearance was visually observed after standing at room temperature for 2 hours.

  (◎: Good, △: Bad gate part, ×: Poor coating)

According to Table 2, it can be seen that the composition of the embodiment exhibits an excellent impact strength, showing a high flow index was excellent in workability and formability. In addition, the softening point, which means the temperature of thermal deformation, showed similar values, but the overall low coefficient of linear expansion coefficient. In addition, in the evaluation of coating properties, it was confirmed that the surface state is excellent and can be directly applied to interior and exterior materials without a primer.

Therefore, according to the present invention; Aromatic vinyl compounds; And optionally a rubber latex, comprising a graft copolymer having three kinds of different monomer compositions and molecular weights. Although the linear expansion coefficient of the resin composition was low and the high temperature dimensional stability was excellent, the impact resistance was confirmed to be improved, and the flow index and the paintability were measured, and the moldability was excellent. . Therefore, it can be usefully used as a substitute material of the conventional ABS, for example, it can be variously applied to interior and exterior materials of automobiles.

Claims (5)

10-30 weight% of graft copolymer (I) containing 30-70 weight% of rubber latex, 70-30 weight% of monomer mixtures which consist of 20-40 weight% of vinyl cyanide compounds, and 60-80 weight% of aromatic vinyl compounds ; 20 to 50% by weight of a non-linear copolymer (II) having 20 to 40% by weight of a vinyl cyanide compound monomer and 60 to 80% by weight of an aromatic vinyl compound monomer, and having a weight average molecular weight of 200,000 to 1,000,000; And 20 to 60 wt% of a linear copolymer (III) having 20 to 40 wt% of a vinyl cyanide compound monomer and 60 to 80 wt% of an aromatic vinyl compound monomer, and having a weight average molecular weight of 100,000 to 200,000; Thermoplastic resin composition, characterized in that it is included. The rubber latex of claim 1, wherein the rubber latex is selected from natural rubber; Styrene-butadiene rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, butyl rubber, acrylonitrile-butadiene A thermoplastic resin composition, characterized in that selected from the group consisting of rubber (acrylonitrile-butadiene rubber), chloroprene and neoprene rubber (synthetic rubber). The thermoplastic resin composition according to any one of claims 1 to 3, wherein the rubber latex has a particle size of 0.25 to 0.40 µm. The thermoplastic resin composition of claim 1, wherein the vinyl cyanide compound is acrylonitrile or methacrylonitrile. The method of claim 1, wherein the aromatic vinyl compound is styrene (alpha) methyl styrene (α-methyl stylene), methyl methacrylate (methyl methacrylate), butyl acrylate (butyl acrylate), N-phenylmaleimide (N- Phenyl maleimide), N-cyclohexyl maleide (N-cyclohexyl maleide), maleic anhydride (anhydric maleic acid), and a thermoplastic resin composition, characterized in that selected from the group consisting of a mixture thereof.